Read Sony NW-A1000 / NW-A1200 Service Manual online
Copying is strictly prohibited
13
2-3. Other generated voltages (2.8V_REG/OEL_VCC/LED_VCC)
Fig.2-2 shows the generated voltages other than the voltages generated by Power Control IC9001.
1. 2.8V voltage
When 3.3V_A voltage is supplied from Power Control IC9001, it is supplied to pin-1[VIN] and pin-6 [CE] of +2.8V REGULATOR IC3001. Then IC3001 starts up. And IC3001
generates +2.8[V] and outputs it from pin-3[VOUT] to D/A CONVERTER IC3002 and HP Amplifier IC3003 as 2.8V_REG voltage.
2. OEL_VCC voltage
Refer to “2-6. Power Control by PLD IC8001” on page 17.
3. LED_VCC voltage (20[V])
When VB voltage is input to pin-5 [VIN] of IC8302, IC8302 starts up. And also, when 3.0V voltage generated by IC9001 is supplied to pin-4 [EN] of IC8302, IC8302 starts
operation. The circuit operates as follows. The step-up DC-DC converter circuit inside IC8302 controls the duty ratio of the PWM waveform which is output from pin-1 [SW],
with monitoring the voltage input to pin-3 [VFB] of IC8302. By this operation, the step-up circuit works, and the LED_VCC voltage (20[V]) is generated.
Fig.2-2 Generated voltages other than the voltages generated by Power Control IC9001
Click on the first or last page to see other NW-A1000 / NW-A1200 service manuals if exist.